Team play?

Hello,
for those of you who have the game already, how much of the game do you fight alongside other NPCs when sneaking throug the subways? Are there alot of sections where you get left by your team and you kind of just sneak alone through dark scary areas or are you pretty much always accompanied by a squad like in call of duty?

What percentage of the game is spend alone in subways? 10%? 80%? Do you recommend this game? I was thinking of renting it.